Since 1979 a new Acquired Immune Deficiency Syndrome has been observed in homosexual and bisexual males, male and female intravenous drug abusers, male and female Haitians, hemophiliacs, and intimate contacts of the aforementioned. Immunologically, the Acquired Immune Deficiency Syndrome is marked by a devastating depression incellular immune function with subsequent development of multiple severe opportunistic infections. This project involves the evaluation of bacteremia caused by Mycobacterium avium-intracellulare in these patients.